code: def create_tree():
      n1 = Node(100)
      n2 = Node(50)
      n3 = Node(150)
      n4 = Node(25)
      n5 = Node(75)
      n6 = Node(125)
      n7 = Node(175)
      n1.left, n1.right = n2, n3
      n2.left, n2.right = n4, n5
      n3.left, n3.right = n6, n7
      return n1
  
imports: from algorithms.tree.traversal import preorder, preorder_rec, postorder, postorder_rec, inorder, inorder_rec
  from algorithms.tree.b_tree import BTree
  from algorithms.tree import construct_tree_postorder_preorder
  from algorithms.tree.fenwick_tree.fenwick_tree import Fenwick_Tree
  import unittest
label_desc: Use image node_id 1 for calling a global function with example usage: create_tree() and returns: n1